2017-02-08 17:33:18 +01:00
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/****************************************************************************
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2018-05-29 21:21:26 +02:00
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* libs/libc/stdio/lib_setvbuf.c
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2017-02-08 17:33:18 +01:00
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*
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2021-03-13 10:30:10 +01:00
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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2017-02-08 17:33:18 +01:00
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*
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2021-03-13 10:30:10 +01:00
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* http://www.apache.org/licenses/LICENSE-2.0
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2017-02-08 17:33:18 +01:00
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*
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2021-03-13 10:30:10 +01:00
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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2017-02-08 17:33:18 +01:00
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#include <stdbool.h>
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2017-02-09 22:04:17 +01:00
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#include <stdio.h>
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2017-02-08 17:33:18 +01:00
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#include <unistd.h>
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#include <fcntl.h>
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2021-05-18 08:59:14 +02:00
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#include <assert.h>
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2017-02-08 17:33:18 +01:00
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#include <errno.h>
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#include <nuttx/fs/fs.h>
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#include "libc.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: setvbuf
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*
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* Description:
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* The setvbuf() function may be used after the stream pointed to by
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* stream is associated with an open file but before any other operation
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* (other than an unsuccessful call to setvbuf()) is performed on the
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* stream. The argument type determines how stream will be buffered, as
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* follows:
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*
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* _IOFBF - Will cause input/output to be fully buffered.
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* _IOLBF - Will cause input/output to be line buffered.
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* _IONBF - Will cause input/output to be unbuffered.
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*
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2019-02-26 01:19:13 +01:00
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* If buf is not a null pointer, the array it points to may be used instead
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2021-03-13 11:55:37 +01:00
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* of a buffer allocated by setvbuf() and the argument size specifies the
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* size of the array; otherwise, size may determine the size of a buffer
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* allocated by the setvbuf() function. The contents of the array at any
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* time are unspecified.
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2017-02-08 17:33:18 +01:00
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*
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2017-02-09 22:04:17 +01:00
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* Input Parameters:
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* stream - the stream to flush
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* buffer - the user allocate buffer. If NULL, will allocates a buffer of
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* specified size
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* mode - specifies a mode for file buffering
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* size - size of buffer
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2017-02-08 17:33:18 +01:00
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*
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2017-02-09 22:04:17 +01:00
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* Returned Value:
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* Upon successful completion, setvbuf() will return 0. Otherwise, it will
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* return a non-zero value if an invalid value is given for type or if the
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* request cannot be honored, [CX] and may set errno to indicate the error
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2017-02-08 17:33:18 +01:00
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*
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****************************************************************************/
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int setvbuf(FAR FILE *stream, FAR char *buffer, int mode, size_t size)
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{
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2017-02-09 16:24:44 +01:00
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#ifndef CONFIG_STDIO_DISABLE_BUFFERING
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2018-08-29 14:07:05 +02:00
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FAR unsigned char *newbuf = NULL;
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2017-02-08 17:33:18 +01:00
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uint8_t flags;
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int errcode;
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/* Verify arguments */
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2021-03-13 11:55:37 +01:00
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2017-02-08 21:06:29 +01:00
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/* Make sure that a valid mode was provided */
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2017-02-08 17:33:18 +01:00
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if (mode != _IOFBF && mode != _IOLBF && mode != _IONBF)
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{
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errcode = EINVAL;
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goto errout;
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}
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2017-02-08 21:06:29 +01:00
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/* If a buffer pointer is provided, then it must have a non-zero size */
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2017-02-08 17:33:18 +01:00
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2017-02-08 21:06:29 +01:00
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if (buffer != NULL && size == 0)
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2017-02-08 17:33:18 +01:00
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{
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errcode = EINVAL;
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goto errout;
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}
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2017-02-08 21:06:29 +01:00
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/* My assumption is that if size is zero for modes {_IOFBF, _IOLBF} the
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* caller is only attempting to change the buffering mode. In this case,
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* the existing buffer should be re-used (if there is one). If there is no
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* existing buffer, then I suppose we should allocate one of the default
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* size?
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*/
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if ((mode == _IOFBF || mode == _IOLBF) && size == 0 &&
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stream->fs_bufstart == NULL)
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{
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2017-02-09 16:53:50 +01:00
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size = BUFSIZ;
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2017-02-08 21:06:29 +01:00
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}
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2017-02-09 22:39:33 +01:00
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/* A non-zero size (or a non-NULL buffer) with mode = _IONBF makes no
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* sense but is, apparently, permissible. We simply force the buffer to
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* NULL and size to zero in this case without complaining.
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*/
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else if (mode == _IONBF)
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{
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buffer = NULL;
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size = 0;
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}
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2017-02-08 17:33:18 +01:00
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/* Make sure that we have exclusive access to the stream */
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lib_take_semaphore(stream);
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2019-02-26 01:19:13 +01:00
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/* setvbuf() may only be called AFTER the stream has been opened and
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* BEFORE any operations have been performed on the stream.
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2017-02-08 17:33:18 +01:00
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*/
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/* Return EBADF if the file is not open */
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if (stream->fs_fd < 0)
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{
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errcode = EBADF;
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goto errout_with_semaphore;
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}
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/* Return EBUSY if operations have already been performed on the buffer.
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* Here we really only verify that there is no valid data in the existing
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* buffer.
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2017-02-08 21:06:29 +01:00
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*
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2021-12-20 15:49:48 +01:00
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* REVISIT: There could be race conditions here, could there not?
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2017-02-08 17:33:18 +01:00
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*/
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if (stream->fs_bufpos != stream->fs_bufstart)
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{
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errcode = EBUSY;
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goto errout_with_semaphore;
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}
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/* Initialize by clearing related flags. We try to avoid any permanent
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* changes to the stream structure until we know that we will be
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* successful.
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*/
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2017-02-09 16:53:50 +01:00
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flags = stream->fs_flags & ~(__FS_FLAG_LBF | __FS_FLAG_UBF);
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2017-02-08 17:33:18 +01:00
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2017-02-08 21:06:29 +01:00
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/* Allocate a new buffer if one is needed or reuse the existing buffer it
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* is appropriate to do so.
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2017-02-08 17:33:18 +01:00
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*/
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2017-02-08 21:06:29 +01:00
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switch (mode)
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{
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case _IOLBF:
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flags |= __FS_FLAG_LBF;
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/* Fall through */
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case _IOFBF:
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2021-03-13 11:55:37 +01:00
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2017-02-08 21:06:29 +01:00
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/* Use the existing buffer if size == 0 */
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if (size > 0)
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{
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/* A new buffer is needed. Did the caller provide the buffer
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* memory?
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*/
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if (buffer != NULL)
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{
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newbuf = (FAR unsigned char *)buffer;
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2021-03-13 11:55:37 +01:00
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/* Indicate that we have an I/O buffer managed by the caller
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* of setvbuf.
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2017-02-08 21:06:29 +01:00
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*/
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flags |= __FS_FLAG_UBF;
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}
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else
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{
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newbuf = (FAR unsigned char *)lib_malloc(size);
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if (newbuf == NULL)
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{
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errcode = ENOMEM;
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goto errout_with_semaphore;
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}
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}
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}
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else
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{
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/* Re-use the existing buffer and retain some existing flags.
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* This supports changing the buffering mode without changing
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* the buffer.
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*/
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DEBUGASSERT(stream->fs_bufstart != NULL);
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flags |= stream->fs_flags & __FS_FLAG_UBF;
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goto reuse_buffer;
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}
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break;
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case _IONBF:
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2021-03-13 11:55:37 +01:00
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2017-02-08 21:06:29 +01:00
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/* No buffer needed... We must be performing unbuffered I/O */
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newbuf = NULL;
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break;
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default:
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2018-08-24 14:21:15 +02:00
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DEBUGPANIC();
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2017-02-08 17:33:18 +01:00
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}
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2017-02-08 18:28:24 +01:00
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2017-02-08 21:06:29 +01:00
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/* Do not release the previous buffer if it was allocated by the user
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* on a previous call to setvbuf().
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*/
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2021-03-13 11:55:37 +01:00
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if (stream->fs_bufstart != NULL &&
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(stream->fs_flags & __FS_FLAG_UBF) == 0)
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2017-02-08 21:06:29 +01:00
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{
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lib_free(stream->fs_bufstart);
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2017-02-08 18:28:24 +01:00
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}
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2017-02-08 21:06:29 +01:00
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/* Set the new buffer information */
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stream->fs_bufstart = newbuf;
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stream->fs_bufpos = newbuf;
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stream->fs_bufread = newbuf;
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stream->fs_bufend = newbuf + size;
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2017-02-08 17:33:18 +01:00
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/* Update the stream flags and return success */
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2017-02-08 21:06:29 +01:00
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reuse_buffer:
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stream->fs_flags = flags;
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2017-02-08 17:33:18 +01:00
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lib_give_semaphore(stream);
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return OK;
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errout_with_semaphore:
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lib_give_semaphore(stream);
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errout:
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set_errno(errcode);
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return ERROR;
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#else
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/* Return that setvbuf() is not supported */
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set_errno(ENOSYS);
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return ERROR;
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#endif
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}
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